Apparatus for the measurement of the level and flow of liquids



June 11, 1929. G. F. SHOTTER 1.716.838

APPARATUS FOR THE MEASUREMENT OF THE LEVEL AND FLOW OF LIQUIDS Filed July 22, 1925 5 Sheets-Sheet l June 11, 1929. G; SHOTTER 1.716.838

APPARATUS FOR THE MEASUREMENT OF THE LEVEL AND FLOW OF LIQUIDS Filed July 22, 1925 3 Sheets-Sheet June 11, 1929. e. F. SHOTTER 1.716.838

APPARATUS FOR THE MEASUREMENT OF THE LEVEL AND FLOW OF LEQUIDS Filed July 22, 1925 3 Sheets-Sheet 3 Patented June 11, 1929.

UNITED STATES PATENT OFFICE.

GEORGE FREDERICK SHOTTER, OF NEW SOUTHGA'I'E, ENGLAND.

APPARATUS FOR THE MEASUREMENT THE LEVEL AND FLOW OF LIQUIDS.

Application filed July 22, 1925, Serial No. 45,348, and in Great Britain September 23, 1924.

This invention relates to apparatus for the measurement of the level and flow of liquids and it has for its object improvements by which certain advantages shall be ohtained.

In the specification of prior British Letters Patent No. 17,014 of 1911, granted to the applicant herein, apparatus is described for the electrical measurement ofthe level or flow of a liquid comprising a main or level measuring pair of electrodes at a fixed distance apart so immersed in the liquid that the resistance between them changeswhen the level changes Within the limits to be ebserved, in combination with a compensating pair of electrodes immersed to a constant degree in the liquid or in liquid of similar polarizing properties, an electrical generator and a resistance indicator which has a control-producing circuit and a circuit to provide a deflecting force, the parts being so connected that the generator, the controlproducing circuit and the compensating electrodes are in one closed circuit and the generator, the circuit .to provide deflecting force and the main electrodes are in a second closed circuit.

The present invention relates to apparatus of the kind described above and more particularly to the construction and arrangement of the electrodes.

According to the present invention, in apparatus for the measurement of the level or flow of liquids of the kind described above a pair of electrodes is mounted on or in a tubular member of insulating material, such as glazed earthenware, of triangular, circular or other section. Preferably one of the electrodes is mounted within; midway of the length and transversely of the tubular member; and the other electrode is in two parts which are mounted at opposite ends of the said tubular member. The tubular member may havea slot midway of its length for the insertion of the electrode and a second tubular member, also of insulating material, surrounding said slot and extending outwards from v the first mentioned tubular member.

v,Forms of the invention will now be described with reference to the accompanying drawings wherein Fig. 1 shows a side elevation in section of one form of the main electrodes,

Fig. 2 shows an end view thereof, and

Fig. 3 shows a plan;

Figure 4 shows an elevation in section of a form of compensating electrodes;

Fig. 5 shows a section at the line A, B or". Fig. 4, and

Fig. 6 shows a complete instrument suspended in liquid, whose height or flow is to be measured. I

Fig. 7 isa diagram illustrating the elec triealconnections of the apparatus.

Referring to Figs. 1, 2 and 3 which show one form of main or level-measuring pair of electrodes, a tubular member 1 of triangular section is formed of insulating material, such as glazed earthenware. Midway of its length, and preferably on the top face is formed an opening 2, extending across the face and through which one of the electrodes is inserted into the interior of the tubular member 1 so as to extend transversely thereof. \Vithin the tubular member is mounted a shield 3, 3 also of insulating material, for example ebonitc, a phenol condensation compound, glazed earthenware, or the like. This shield is in two parts and extends from each side of the opening 2, to the ends of the tubular member. Conveniently it is in a. number of parts 3, 3 all exactly similar and provided with positioning means, such as co-operating pins and depressions 4 in adjacent faces, so that they are easily mounted in correct relationship. The shield is of a shape to produce a sectional area and shape of path between the electrodes such that the relationship between the area of path and the-flow of the liquid over a notch with which the apparatus is employed is expressed by a straight line law. The shape of the shield is such that the difference between the area of the triangular shape, minus the area of the shield is, for all heights above the zero or apex of the path, proportional to the flow of the liquid over the notch, viz

(Area ottriangular path-area of shield at h ei ght g Flow at height X when the zero of the path is at the same level as the zero of the notch.

In the case of a V notch this diflerential area is proportional to H and in the case of a rectangular notch to H A shield of the shape shown in the drawings is employed when the apparatus is used with a V-notch; for the other notches or other sections of tubular member the shape of the shield will vary. In some cases the shield a constant may be dispensed with. The sections of the shield adjacent the central electrode and the outer ends of the tubular member are secured by screwed rods 6 mounted on hushed holes Tinthe top face of the tubular member 1. Each rod (3 engages a hole in a plate 9 secured by screws 10 to the last section of'the shield. It will be understood that variousmeans may be employed'for positioning and securing the end sections of the shieldyfor example, the rods '6 may engage holes in said end sections.

The tubular member is carried by a frame 11 arranged at each end. These frames are conveniently of cast metal. The tubular member 1' rests on adjustable studs 12 which project from the two walls ofeach frame which are arranged at an angle corresponding with the angle of'the tubular member.

.The two upper sides 13 of the frame 11 slope" upwards-and at-"tlieir junction is formeda boss 14,'through which passes a threaded rod 15 secured by nuts, 16, 16. At itsupper end the rod, is carried by a sleeve 17 on a rod 18 which is'carried on suitable supports 19'(see Fig. 6) in or above the container for the liquid in connection with which the instrument is employedv A ing to the upper'part ofthe gauze'25.

.whieh are pivoted-so that -they maybe further rod 20 is pivotally mounted zit-21 on a side 13 of one of the frames 11. The upperend of the rodQO is threaded and secured by. nuts 22gt0 a: bracket 23 on'the support 19. 7

, Thefceiitralelectrode'5 which is usually the anode is of platinized gauze of a shape corresponding with the interior ofthe tubular member 1, witliltlie centre portion, of a shapecorrespondingto that of the shield 3, removed. The edges ofthe inneror shaped part ofthe gauze are clamped between two pieces of insulating materiah'such as ebon- 'ite,"'or the material known under the registered trademark bakelite, of the same section as the shield 3, anda stiff wire soldered round the outer edge. ieflexib'le conducting strip 24, such as phosphor} bronze is electrically connected as by solden This strip is secured by a screw 26, and soldered between the bifurcated ends of a conducting rod 27; 'The rod 27 is clamped between 'two bars 28 ofinsulating materialand it passes f through an insulator 29 to a terminal 30. The electrode is positioned by packing strips or plugs inserted in the'sl'ot-s 2 at its ends and it is'heldinposition by spring clips. 31

moved overthe top of the bars, '28, 28'.

he other electrode,- usually the cathode, is in two parts mounted at opposite ends of the tubularn'ie'mber 1.- Each part consists of a sheet of meta-l'gauze, such as of nickel platedcopper 32, of substantially the same shape astlie inte'io'r of the tubular member 1,.and with the centre portion of ashape corresnonding to the section of the shield-3,

,sss,

'e 11;;- this opening.

e trod removed. The gauze is mounted ina frame 33, which'may be of angle or U-section, by

soldering on one face thereof so that it may i be brought up level with the end of the tubular member 1. p

The upper bar of the frame is secured, as by screws, to abar 34 oi": insulating material, and the lower end of the frame is ofengageinent with-the bar 345 At the lower .end t-he block 35 rests in a bracket 37, mounted on a frame 11. The size and mounting of the electrodes is such that'they are. just clear from the ends of the tubular member 1. "lVhen the shield 3' is dispensed with the centre portion of the gauze is not removed. The two frames 11 are connected by rods 38. On each bracket 37 is mounted a gauge member 39. on each bar '34 is mounted a terminal 40 whichis electrically connected to the gauze 32. ii I Figures 4 and 5 show one form of compensating electrodes. A, hollow cylindrical member 76' of glazed earthenware has an opening at about the middle extending half way round and a tubular extension 77 cov- Tl'lQ'tlHOClQ 78 of the wire gauze is of circular form'andis'inserted in the centre of the tube 76 through the hollow extension 77; 'The cathode is in two parts 79,79 which may be arranged one over each: endof the cylindrical member '76, butpreferably they are positioned'by being inserted through hollow extensions 80, 81, arranged at opposite ends of tlie'tube 76. The electrodes are of wire gauze and are conveniently constructed by clamping the gauze between two insulating parts,'82,

83. The electrical connection to the gauze.

is made by a wire passing between the two parts 82,83 to a metalrod 84' mounted in insulators 85 and connected to a terminal 7 ring from the invention. The tubular ieinbenTG is carried by. frames 87 of ring formand'rods 88.

78, and it will be understood that in use the le el measuring pair elees'are supported in the liquidwhose heightor iiow isto be measured in such a POSltlOZktlitt the surface of the liquid does not riseabove thelevel of the-topof the inside oii-thc tubular in mberhi'iii and on which theelect'rodes are mounted, and does not fall below the bottom of'the insideI'o-f thetubul'ar member. The eo'inpen] pair of electrodes are supported 'in such a way 7 i; Y," '1 m lml- 1 Lila L183 are a Mays compl te yiinineised in liquid of similarpola'rizing properties, to

the liquid in'which the main o -"level inc-as,

uring electrodes are supported andthetei m a controlling :lorce in the instrument.

liquid of similar polarizing properties is in the specification and claims to be understood to cover theliquid whose level is being measured.

The electrical circuits connecting the electrmles and the indicating device are shown in diagram in Fig. '7. in this diagram the compensating electrodes are indicated at 5t. (it and the main electrodes at and 32. One of the co:upensatingelectrodes (H is connected to one of the main elect-odes 5 and the junction is connected to one pole of an electric battery 90 whose other pole is connected to a point 91 where the circuit biturcates. Ore path from this point of bifurcation is through a coil 92 of the resistance ii'nlicator to the main electrode 32, while the other path from the point 91 is through two coils 93, 9d oi" the resistance indicator arranged in series with one another, to the compensating electrode 54-. The coils 93, 94.- are arran d to produce nnignetic fluxes at right angles to one another which combine to give The coil 92 provides a deflecting force in the vicrni ot a magnetic flux helping or opposing that produced by the coil Oil. The controlling and deflecting forces operate conjointly upon a piece 01? moving iron in any manner which is well known in electrical instruments. It will be rerulily observed that the arrangement of the coils 92, 93, SH; embodies the principle commonly employed in an olnmneter and the iiulications of the instrument are therefore such as with suitable graduation of the scale will indicate the resistance between the electrodes 82 and 5 -iinlcpendcntly of the voltage applied by the bat [cry 90 and also indcqiendently of the E. M. l of polarization, since this latter E. M. 1*. operates in, and in the same direction in both the circuit containing the coil 92 and that containing the coils 925, 94. The resistance between the electrodes and varies in accordance withthe height of the liquid. Since the flow of the liquid is a function of the level measured by the instrument the scale may be calibrated, to read height or [low of the liquid. \Vhen the apparatus is employed to measure flow of liquid over a notch, the bottom of the main electrode is arranged so that it is just level with the bottom of the notch. Such an arrangement is illustrated in Fig. 6 in which 89 indicates a V-notch. The instrument is calibrated bymeans of a hook gauge applied to thepart 39.

The term of standard path or compensating electrodes illustrated in Figs. l and is preferably used. in connection with high conductivity liquids.

The electrodes have been described as constructed of wire gauze, but it will be understood lhatthey may, if desired, be formed of wire, preferably platinum or platinized wire wound on frames of insulating material. Further the gauze may be of other metal than platimzed copper, such for example as nickel or ferro-nickel, though platinum or platinizcd metal is pre'lei'red.

The well known system of guard wiring may be applied to the apparal us for the purpose of preventing the img-asurement ol leakage currents.

It will be understood that various modifications may be made without departing from the invention. For example, the shield instead of being made up of parts 3, may, if desired, be solid.

Recording apparatus and/or integrating apparatus for example that described in the specilicat ion of my prior British Letters Pa."- ent No. 163,739 may be employed in conjunction with the apparatus according to the present invention.

If it is necessary or advisable in any par- :irular case to constiuct the tubular member of the main electrode system in two or more parts which have to be jointed, it may bein'lvantagcous to provide a leakage path of known dimensions below the bottom ot the electrode, and in these circumstances the leakage current through this path will be compensated for by passing a small portion of the standard path current through the third coil on the indicator, opposing the coil carrying the current flowing between the. main electrodes.

What I claim is:

1. For apparatus of the kind described for the electrical measurement of the level of a liquid in combination a horizontal openended tubular carrier of insulating material havin a slot midway of its length and a pair of electrodes one inserted through the slot and mounted transversely of said tubular carrier midway of its length and the other electrode in two parts mounted at opposite ends of the tubular carrier.

2. For apparatus of the kind described for the electrical measurement of the level of a liquid in combination a horizontal openended tubular carrier of insulating material having a slot midway of its length, a main pair of electrodes to be immersed in the liquid that the resistance between them changes when the level changes within the limits to be observed one electrode inserted through the slot and mounted transversely of said tubular carrier midway of its length and the other electrode in two parts mounted at opposite ends of the tubular carrier and a fixed shield between the electrodes of a shape to produce a desired relationship between the current which flows between the electrodes and the height of the liquid therebetween.

3. For apparatus of the kind described for the electrical measurement of the level of a liquid in combination a horizontal openended tubular carrier of insulating material l between, sa

having aslot midway of its lei pair of'electrodes to be so imihci liquid that the resistance between th m' of said tubular carrier midwa and the other electrode lILhVJO partsmou'nted p w misses having a slot midway of its {jlengtln a main pair of electrodes to be so immersed in the liquid that the resistance between them changes when the level: changes within the limits to be observed'one electrode inserted through'the slot and mounted transversely of said tubular carrier midway of its length and the other electrode in two parts mounted at opposite ends of the tubular carrier and a fixed shield he-tween theelectrodesof a shape to produce des 'il relationship between th'e current which flows between the electrodes nd the height of the liquid theresh eld being'builtup of a'nuin :ber of parts or insulatingmaterial ei' fsimi section arrange-disco to face and each having positioning means.

'4. Forapparatus of the'lrind described for the electrical measurement of the level of a liquid in'combination a horizontal openended' tubular carrier 01': insulat ng material h s ma n d in the changeswhen the level changes within the limits to be observed one electrode inserted through the slot and mounted"transversely of its length i the electricalmeasurement of ti 0 level of a liquid in combination a horizontahopen ended tubular-carrier of insulating material havin a slot niidwa of len' th a main b r c1 7 pair oielectrodes to be so innnersed in the liquid that the resistance between them changes when the level changes within the limits-to "be'observed on electrodes lnserted through the-slot and mounted transversely ofsaid tubular carrier midway of its length and the other electrode in two parts mounted at opposite ends of the tubular carrierya fixed shield betweenthe electrodes of a shape to produce a desired relationship between the current which between the electrodes and the height of the liquid therebetween, frames to carry the tubular carrier and tosnspend the frames from asupport. 6, F0 apparatus of the kind described for the electrical measurement of the level of-a liquid in combination a horizontal openended tubular carrler of insulating material having a slot midway of its length, a main pair oi" electrodes to'be so immersed in the liquid that the resistance between them changes when the level changes within the limits to be observed one electrode Inserted through the slot and mounted transversely of said tubular. carrier midway of its length and the other ele V at opposite ends of the tubular 021111617, a iii n shield between] the electrodes of r a shape to produce a desired relationship be icon the current which flows between the electrodes and the height of the liquid therebetween, :lramesto carry thetubular carrier,

means to suspend the'frames froinla support an d a shield between the electrodes-of a shape to produce desired relationship between the current which 'iiows' between' the clcc-' trodes and the height of the liquid therebetwee n. i a

For-npparatusof the kind described for the electrical measurement of the level of a iqnid in combination a horizontal openended tubular carrier of insulating material and a pair of electrodes mounte il transversely thereof one within, midway of the length of said tubular carrier and, the other in two parts mounted atopposite ends off d tubular carrier. 7 I

Mode in two parts mounted scones i n'nnnn on SHUTTER.

min.- Maw 

